Abstract
BACKGROUND/AIM: Chronic lymphocytic leukemia (CLL) is currently incurable. CLL is characterized by disordered DNA methylation. The aim of the present study was to target methylation with methionine restriction in a patient with progressive CLL. CASE REPORT: Methionine restriction for the patient was achieved with a low-methionine vegan diet and oral recombinant methioninase (o-rMETase). The patient also received rituximab, once per week for four weeks, and acalabrutinib 100 mg, twice daily (bid) continuously. The patient's white blood cell count decreased by 95% from peak levels and extensive lymphadenopathy disappeared during combination treatment with o-rMETase, rituximab, and acalabrutinib. CONCLUSION: The combination of methionine restriction and first-line chemotherapy resulted in an apparent complete response (CR) in a CLL patient, a rare event. The duration of the CR will be monitored, and additional CLL patients will be treated similarly in the future.